METHOD FOR PRODUCING A NON-POLAR A-PLANE GALLIUM NITRIDE (GAN) THIN FILM ON AN R-PLANE SAPPHIRE SUBSTRATE

摘要

A method for producing a non-polar a-plane gallium nitride (GaN) thin film on an r-plane sapphire substrate using metal organic chemical vapour deposition (MOCVD) technique, the method comprising the steps of: annealing the r-plane sapphire substrate using a hydrogen cleaning process; depositing a GaN nucleation layer in the presence of vaporized sources of gallium and nitrogen on the substrate; depositing and growing a GaN buffer layer atop the nucleation layer; and laterally growing a GaN overgrowth layer atop the buffer layer, wherein the step of depositing and growing of the layers are conducted under a standardized volumetric flow rate of the nitrogen source within a range of 0.5 to 2.1 slm. Particularly, the method also comprises controlling V/III ratio, reaction temperature and flow rate of reactants during growth of GaN layers. It was found that such method could result in reduced lattice mismatch between each layer.